LED has been applied to cellular phones, various display devices, and the like owing to characteristics such as electric power saving, long life, and small size. With an improvement of light emission efficiency thereof, LED has been rapidly coming into wide use also in illumination uses.
Currently, in white LED illumination, the mainstream is a method where blue LED and a phosphor emitting a yellow light that is a complementary color of blue are used in combination to obtain a white light. As the phosphor, YAG (yttrium aluminum garnet)-based ceramics have been frequently employed.
For example, Patent Document 1 describes a ceramics composite having a phosphor phase composed of YAG containing Ce and a matrix phase composed of at least one of Al2O3 and AlN. The ceramics composite obtained from a phosphor as above has a simple constitution but an excellent emission intensity can be obtained.
Patent Document 1: JP-A-2011-12215